import java.lang.reflect.Array;
import java.util.Arrays;

public class Test {
    public static void transform(int[] arr1){
        for(int i = 0;i < arr1.length;i ++){
            arr1[i] = arr1[i] * 2;
        }
    }
    public static void main(String[] args) {

        int[] arr = {1, 2, 3};
        transform(arr);
        System.out.println(Arrays.toString(arr));
    }
}
